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A new approach to the formation of hierarchical porous structure of mordenite without use of templates is suggested in the presented work. The method is based on the crystallization of mordenite in granules consisting of amorphous aluminosilicate (metakaolin), fumed silica and mordenite crystals, provided that the crystalline phase content must be higher than that of the amorphous phase. The synthesized material is characterized by high crystallinity (up to 92%) with the volume of micro-, meso- and macro-pores of 0.15, 0.20 and 0.18 cm3/g, respectively. The research results showed that MOR type zeolite with a hierarchical structure in the H-form has total acidity in ammonia of about 860 µmol/g and after promotion of 0.3% wt platinum exhibits high activity and selectivity in the hydroisomerization of a model mixture of benzene–heptane into methylcyclopentane and isomers of n-heptane.

The aluminum rich mordenite (Si/Al wt% ~7) sample has been treated with various acids i.e., hydrochloric acid (MOR-HC), nitric acid (MOR-HN) and oxalic acid (MOR-Ox) so as to facilitate the dealumination and mesopore creation in the mordenite. The parent as well as acid treated samples have been characterized by XRD, FTIR, SEM, TEM, BET, N2 adsorption–desorption, porosity and NH3–TPD. The resultant samples have been applied for their catalytic activity towards selective oxidation of benzyl alcohol to produce benzaldehyde at solvent-free liquid phase reaction, using H2O2 as oxygen source. Irrespective to the nature of acid, all the dealuminated samples exhibited increase in surface area, external surface area, pore volume and mesopore volume, while the highest increase appeared in case of MOR-HN. This phenomenon also reflected in the selective oxidation activity of the samples, where all the acid treated samples exhibited improvement in the benzyl alcohol conversion and benzaldehyde yield. The highest conversion of >99 % along with as high as >100 % selectivity to benzaldehyde was obtained on MOR-HN catalyst. This particular catalyst also exhibited excellent reusability suitable for its industrial applications.

Hierarchical mesoporous zeolites with different levels of micro- and mesoporosity were prepared by dissolution and reassembling processes of MOR zeolite in the presence of mesoscale cationic surfactant cethyltrimethylammonium bromide. The obtained materials were characterized by X-ray diffraction, Scanning electron microscopy, Transmission electron microscopy, Fourier transform infrared, Nitrogen (N2) adsorption/desorption, Temperature programmed desorption of NH3 (NH3-TPD) and Nuclear magnetic resonance techniques. Moreover, these hierarchical zeolites were tested as hydrocarbon traps using toluene as probe molecule and the temperature programmed desorption method. The results showed that the amount of microstructure and mesostructure in the composite was able to be favorably tuned by varying dissolution time at the first stage. The hierarchical materials displayed remarkably high desorption temperature in toluene-TPD, which is an expected performance of hydrocarbon trap in automobile tailpipes. The effect is due to the easier transport of bulky molecules provided by mesopores and increasing the number of available active sites via a fragmentation of the microporous framework. Therefore, the synthesized composite molecular sieve may be a novel catalyst for hydrocarbon trap in automobile tailpipes.

The influence of pseudo-boehmite binder on the catalytic properties of dealuminated mordenite (MOR) catalyst for Friedel–Crafts alkylation was investigated. Solid-state 27Al MAS NMR spectroscopy, temperature-programmed desorption of ammonia (NH3-TPD), BET surface area measurement and catalyst particle mechanical strength were used to characterize the catalysts. It was observed that the addition of pseudo-boehmite binder results in improvement in terms of pore size distribution and its mechanical strength. Furthermore, the dredged pore path of MOR was not destroyed although the acid amount and acid type were adjusted properly when the modified MOR was calcinated. Among these catalysts studied, the catalyst bound with 10 wt% pseudo-boehmite binder showed the best catalytic performance in terms of yield and stability, which can be attributed to its maximum medium strong acid amount and its structural properties which is favorable for fast diffusion of products.

Framework-substituted Co-mordenite zeolite was synthesized by a dry gel conversion (DGC) method, using inorganic raw materials of silica sol, aluminum sulfate, cobalt nitrate and sodium hydroxide. Typical synthesis conditions were Co/SiO2 = 0.01–0.05, SiO2/Al2O3 = 20–50, H2O/SiO2 = 40, Na2O/SiO2 = 0.4 molar ratios, 170 °C, and 3 days. The obtained samples were characterized by X-ray diffraction, UV–vis, scanning electron microscope, and nitrogen sorption technique. The results showed that Co ions were incorporated into the tetrahedral framework structure of mordenite without forming extra-framework Co species. Products obtained by the present all-inorganic systems possessed open micropores and required no traditional high-temperature calcination. The DGC approach also avoided the separation of the final product from solvent phase.

Large, pure mordenite (MOR) crystals were synthesized hydrothermally using silicic acid powder as the silica source, and the synthesized MOR samples were characterized by XRD and SEM techniques. The effects of several synthesis parameters, such as particle size and heat pre-treatment temperature of the used silicic acid powder as well as SiO2/Al2O3 molar ratio and alkalinity in the synthesis solution, on the formation of MOR crystals were systematically investigated. The results indicate that the low solubility of the silicic acid powder, resulting from the use of the powder with large particle sizes or its heat pre-treatment at high temperatures, leads to the formation of unwanted α-SiO2 phase. Additionally, a low ratio of SiO2 to Al2O3 and a high alkalinity in the synthesis solution can result in the formation of analcime-type (ANA) zeolite. Large, pure prismatic MOR crystals with uniform size and shape can be synthesized hydrothermally at a high ratio of SiO2 to Al2O3 and a low alkalinity in the synthesis solution using silicic acid powder with fine particle sizes without heat pre-treatment as the silica source. The synthesized MOR crystals with acid treatment can significantly enhance their micropore accessibility.

Transition metal-containing mordenite have been prepared by solid state ion exchange with microwave irradiation of mechanical mixtures of CoCl2o6H2O, NiCl2o6H2O and CuCl2o2H2O with mordenite at 750 W microwave power and for 10-20 min treatment time. The prepared transition metal-mordenite were characterized by X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FT-IR), simultaneous TG and DTA thermal analyses (TG/DTA), surface area measurement (BET), and diffuse reflectance spectroscopy (DRS). The results show that Co2+, Ni2+, and Cu2+ metal ions are actually incorporated into mordenite pores. The extra-framework locations of metal cations were determined Rietveld refinement of XRD data, performed in the Cmcm space group for all three samples. Three metal sites were located: the first site is in an almost perfect boat-shaped coordination with framework oxygen's, the second site is poorly coordinated while the third metal cation site was found at the center of mordenite cage in six-fold coordination to water molecules.

The Al distribution in high-silica mordenite (MOR) zeolites with various Si/Al ratios was investigated by FT-IR spectroscopy in the presence of CD3CN probe molecules and benzene adsorption. Two adsorption bands assigned to CN stretching vibration were observed at 2280–2295 and ≈2315 cm−1, which are due to interaction of CN with acidic hydroxyl groups in the main channels and the side pockets of H-MOR zeolite, respectively. The relative intensity of the peak at 2315 cm−1 increased with an increase in the Si/Al ratio, indicating that the proportion of Al atoms in the main channels relatively decreased with the Si/Al ratio. This was confirmed from the linear relationship between the number of benzene molecules adsorbed in a unit cell and the number of Al atoms in the main channels. In addition, this was also suggested from the computer simulation result that Al atoms are preferentially sitting in the T3 site.

Synthesis of 2,6-divinylpyridine (2,6-DVP) and 2-methyl-6-vinylpyridine (2M6VP) was achieved for the first time by side-chain alkylation of 2,6-lutidine using formaldehyde (37 wt/v) as alkylating agent in heterogeneous conditions at atmospheric pressure, and at a reaction temperature of 300 °C over alkali and alkaline metal ion modified zeolites. A mixture of 2,6-divinylpyridine and 2-methyl,6-vinylpyridine were formed by the alkylation of the 2,6-lutidine over Li, Na, K, Rb, Cs, Mg, Ca, Sr and Ba metal ion modified zeolites. The catalytic activity of 2,6-lutidine was studied over various potassium metal ion modified zeolite molecular sieves like ZSM-5 (30), X, Y, mordenite and MCM-41. Alkali modified ZSM-5 (30) catalyst was found more active in side-chain alkylation of 2,6-lutidine when compared to other zeolites. Among all these catalysts studied K modified ZSM-5 (30) gave best conversion of 2,6-lutidine and selectivity to 2-methyl,6-vinylpyridine. K-ZSM-5 (30) catalyst was employed to study the reaction parameters like reaction temperature, weight hourly space velocity, molar ratio, and time on stream for 2,6-lutidine. The effect of potassium metal ion content and precursors of potassium ion on catalytic activity in side-chain alkylation of 2,6-lutidine was studied. The bifunctional catalyst is required containing medium or weak acidic centers and basic centers in the side-chain alkylation, which is understood through proposed mechanism. The selectivities of 2,6-DVP were 45.2, 40.0, and 30.7% at 73.4, 66.0 and 60.5% conversion at 300 °C from 2,6-lutidine and formaldehyde over K-ZSM-5 (30), Rb-ZSM-5 (30) and Cs-K-ZSM-5 (30), respectively.

The catalytic side-chain alkylation of 2-picoline with formaldehyde (37 wt/v) was studied over alkali and alkaline earth metal ion modified zeolites in vapor phase conditions at atmospheric pressure, and at a reaction temperature of 300°C. A mixture of vinylpyridine and ethylpyridine were formed by the alkylation of the corresponding picoline over Li, Na, K, Rb, Cs, Mg, Ca, Sr and Ba metal ion modified zeolites. The catalytic activity of side-chain alkylation of 2-picoline was studied over various alkali modified zeolite molecular sieves like ZSM-5 (SiO2/Al2O3 = 30), X, Y, Mordenite and MCM-41. Alkali modified ZSM-5 (30) catalyst was found more active in side-chain alkylation of 2-picoline when compared to other zeolites. Among all these catalysts studied K modified ZSM-5 (30) and K-Cs-ZSM-5 (30) gave best conversion of 2-picoline and selectivity to vinylpyridine. Cs-ZSM-5 (30) and K-ZSM-5 (30) were employed to study the reaction parameters like reaction temperature, weight hourly space velocity, molar ratio, and time on stream for 2-picoline independently. The effects of alkali metal ion content (K, Cs) and precursors of potassium ion on catalytic activity in side-chain alkylation was studied. An attempt has been made to correlate between the basicity with the activity of side-chain alkylation. The bifunctional catalyst is required containing medium or weak acidic centers and basic centers in the side-chain alkylation, which is understood through proposed reaction mechanism. The selectivities of 2-vinylpyridine were 81.7, 90.8, and 94.8% at 65.4, 62.1 and 57.2% conversions at 300°C from 2-picoline and formaldehyde over K-ZSM-5 (30), Rb-ZSM-5 (30) and K-Cs-ZSM-5 (30) respectively.

Zeolite thin films are interesting for their potential application in membrane based separations, catalysis, and molecular sensing. Mordenite is a one-dimensional channel type zeolite that has been used in alcohol/water separations. Pulsed-laser deposition has been used to prepare partially oriented, crystalline mordenite thin films on stainless steel foil, and frits as well as carbon fibers and DAM-1 particles. Preliminary results for pervaporation of isopropanol/H2O mixtures using mordenite membranes indicate separation factors of 133 and 459 at room temperature and 76°C, respectively.

ZSM-5 (SiO2/Al2O3 = 55) and mordenite (SiO2/Al2O3 = 48) were synthesized directly using poly(ethylene glycol) (PEG 200) as a structure-directing agent. The PEG 200 molecules were occluded in the pores of ZSM-5 but not in mordenite. It is expected that the formation of ZSM-5 occurs via a layered phase such as magadiite.

Molecular modelling, utilising the Grand Canonical Monte Carlo method, was employed to study the interactions between nitrous oxide (N2O) and nitric oxide (NO) with a solid matrix, namely mordenite, before and after charge equilibration. The results indicate that the charge equilibration leads to an adsorption which is independent of the pressure. Comparison with gas-chromatographic experiments indicate that charge equilibration is not allowed in acid mordenite. Therefore, in the case of polar molecules, their adsorption depends on the charge in the zeolite micropores.

Manganese catalyzed decomposition of hydrogen peroxide in the presence of various zeolites was investigated at different pH values, Mn concentrations and zeolite : Mn ratios. Depending upon the level of these parameters the zeolites studied displayed both catalytic and inhibitive effects on the rate of decomposition. At a high pH (10.8) Mordenite 10A in a twofold excess on an ion-exchange capacity basis acted as an inhibitor whereas the other zeolites had little or no effect on the reaction rate. At a lower pH (9.0) zeolite A when added in large excess resulted in a remarkable inhibitive effect whereas the same zeolite resulted in a promotion of the catalytic action of manganese at an intermediate pH (9.9). The complex catalytic nature of zeolite-peroxide-Mn systems is discussed.

In this work the DFT calculations were carried out by means of Gaussian09 program for chosen model cluster—mor Composite Building Unit of zeolites structures. Vibrational frequencies computations and infrared spectra were obtained subsequently for above model. The results of calculations have been compared with IR (MIR and FIR range) spectroscopic studies of zeolites belonging to 5-1 structural group (mordenite and ferrierite) after heavy metal cations (Ag+, Zn2+, Cd2+, Pb2+, and Cr3+) immobilization. Changes in intensities and positions of the bands corresponding to the characteristic ring and Me–O vibrations have been observed. These rings occur in pseudomolecular complexes (built of [SiO4] and [AlO4] tetrahedra) which constitute the secondary building units and form zeolite framework. Based on the results of DFT method calculations, normal vibrations of the 5-1 unit terminated by different cations (Na+, K+) have been visualized. Obtained results have been applied for interpretation of experimental spectra of selected zeolites. The most significant changes have been determined in the region of pseudolattice vibrations (800–500 cm−1), as well as Me–O vibrations (below 400 cm−1). It was proven those cations’ sorption causes changes in the experimental spectra of zeolites. Sorption has been conducted on monoionic forms of mordenite and ferrierite. Based on the results of the sorption/desorption experiments, the proportion of ion-exchange to chemisorption in the process and the effective cation exchange capacity of the individual samples have been estimated. Results of AAS studies have been compared with those obtained by vibrational (IR and Raman) spectroscopy. Changes in intensities and positions of the bands corresponding to the characteristic ring vibrations, due to the immobilization of heavy metal ions, have been observed.